1. Field of the Invention
The present invention relates to a semiconductor device such as a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor).
2. Description of the Related Art
A power semiconductor device typified by a power MOSFET and an IGBT (Insulated Gate Bipolar Transistor) is a compact semiconductor element (semiconductor chip), structured to include a plurality of cells with commonly connected gates formed on a semiconductor substrate, and is capable of quick switching with a low on-resistance. It allows a large current to flow efficiently and responds to a high frequency. Accordingly, it is remarked as a part for power sources in compact electronic machines (such as personal computers and cell phones), for example.
A gate routing wire is employed to connect a plurality of gates commonly. The gate routing wire is connected to a gate electrode pad. Different structures of the gate routing wire have been proposed so that a lowered resistance of the gate routing wire can reduce power consumption in the machine. One is a double-layered structure, which includes a polysilicon film, or the same material as the gate, and an aluminum film disposed on the polysilicon film via an interlayer insulator film (JP-A-2001/36081, FIG. 1). Another is a single-layered structure of an aluminum film (JP-A-7/45817, FIGS. 1–3).
The formation of such the gate routing wire may invite a lowered yield from a short circuit between electrodes when the electrodes in the semiconductor element are electrically connected to external, resulting in a problem associated with reliability.